A US woman who shot and killed her husband and two adult children before taking her own life is thought to have committed the shocking crime as a result of being ostracised from the religion she was raised in.

A federal judge sentenced a former Arkansas judge Wednesday to five years in prison — a stiffer punishment than prosecutors recommended — after he admitted giving young male defendants lighter sentences in return for personal benefits that included sexual favours.

Every time I tell a mate I’m doing a story on cryptocurrency, they invariably ask me the same two questions: should they invest their own hard-earned money, and which cryptocurrency will get them a Lamborghini/yacht/island quickest?

In a 60 Minutes online exclusive, reporter Liz Hayes quizzed Australian Prime Minister Malcolm Turnbull on his relationship with the unpredictable Twitter aficionado and US president Donald Trump ahead of their meeting at the White House Friday.

World must prepare for viruses like 'war'

The Western world must learn from its disastrous response to the Ebola epidemic and prepare for future global outbreaks as if it was preparing for war, according to a US public health expert.

Professor Lawrence Gostin, a global health law expert from Georgetown University in the US, says the delayed reaction to West Africa's outbreak of Ebola - the product of bureaucratic hand-wringing and cultural self-interest - was simply "unconscionable".

"Germs don't know boundaries," he told AAP.

"There will come a time when there will be a disease that will devastate high-income countries.

"I hope we don't wait until it's too late."

Prof Gostin is in Brisbane for the Biosecurity in a Globalised World conference and warned his host nation against assuming it can lock down borders to ward off viral pandemics.

Even with Australia's advanced health system, a major epidemic would exhaust vaccine supplies and health workers, and cause hysteria among the population.

"The politics and the panic are in many ways worse than the virus itself," he said.

Prof Gostin said "nasty" pathogens, climate change and international travel have all increased the likelihood of future global infections.